Inflammatory bowel disease (IBD) is a chronic inflammatory autoimmune condition of the gastrointestinal (GI) tract, which presents clinically as either ulcerative colitis (UC) or Crohn's disease (CD). CD is a chronic transmural inflammatory disease with the potential to affect any part of the entire GI tract, and UC is a mucosal inflammation of the colon. Both conditions are characterized clinically by frequent bowel motions, malnutrition, and dehydration, with disruption in the activities of daily living. CD is frequently complicated by the development of malabsorption, strictures, and fistulae and may require repeated surgery. UC, less frequently, may be complicated by severe bloody diarrhea and toxic megacolon, also requiring surgery. Both IBD conditions are associated with an increased risk for malignancy of the GI tract. The etiology of IBD is complex, and many aspects of the pathogenesis remain unclear.
The treatment of moderate to severe IBD poses significant challenges to treating physicians, because conventional therapy with corticosteroids and immunomodulator therapy (e.g., azathioprine, 6 mercaptopurine, and methotrexate) is associated with side effects and intolerance and has not shown proven benefit in maintenance therapy (steroids). Monoclonal antibodies targeting tumor necrosis factor alpha (TNF-α), such as infliximab (a chimeric antibody) and adalimumab (a fully human antibody), are currently used in the management of CD. Infliximab has also shown efficacy and has been approved for use in UC. However, approximately 10%-20% of patients with CD are primary nonresponders to anti TNF therapy, and another ˜20%-30% of CD patients lose response over time (Schnitzler et al., Gut 58:492-500 (2009)). Other adverse events (AEs) associated with anti TNFs include elevated rates of bacterial infection, including tuberculosis, and, more rarely, lymphoma and demyelination (Chang et al., Nat Clin Pract Gastroenterol Hepatology 3:220 (2006); Hoentjen et al., World J. Gastroenterol. 15(17):2067 (2009)). No currently available therapy achieves sustained remission in more than 20%-30% of IBD patients with chronic disease (Hanauer et al., Lancet 359:1541-49 (2002); Sandborn et al., N Engl J Med 353:1912-25 (2005)). In addition, most patients do not achieve sustained steroid-free remission and mucosal healing, clinical outcomes that correlate with true disease modification. Therefore, there is a need to develop more targeted therapy in IBD that is optimized for chronic use: an improved safety profile with sustained remission, particularly steroid-free remission and prevention of long-term complications in a greater proportion of patients, including those patients who either never respond to an anti TNF therapeutic agent or lose response over time (TNF inadequate responder patients or TNF-IR patients).
The integrins are alpha/beta heterodimeric cell surface glycoprotein receptors that play a role in numerous cellular processes including leukocyte adhesion, signaling, proliferation, and migration, as well as in gene regulation (Hynes, R. O., Cell, 1992, 69:11-25; and Hemler, M. E., Annu Rev. Immunol., 1990, 8:365-368). They are composed of two heterodimeric, non-covalently interacting a and 13 transmembrane subunits that bind specifically to distinct cell adhesion molecules (CAMs) on endothelia, epithelia, and extracellular matrix proteins. In this manner, integrins can function as tissue-specific cell adhesion receptors aiding in the recruitment of leukocytes from blood into nearly all tissue sites in a highly regulated manner, playing a role in the homing of leukocytes to normal tissue and to sites of inflammation (von Andrian et al., N Engl J Med 343:1020-34 (2000)). In the immune system, integrins are involved in leukocyte trafficking, adhesion and infiltration during inflammatory processes (Nakajima, H. et al., J. Exp. Med., 1994, 179:1145-1154). Differential expression of integrins regulates the adhesive properties of cells and different integrins are involved in different inflammatory responses. (Butcher, E. C. et al., Science, 1996, 272:60-66). The beta7 containing integrins (i.e., alpha4beta7 and alphaEbeta7) are expressed primarily on monocytes, lymphocytes, eosinophils, basophils, and macrophages but not on neutrophils (Elices, M. J. et al., Cell, 1990, 60:577-584).
The α4β7 integrin is a leukocyte-homing receptor that is important in the migration of cells to the intestinal mucosa and associated lymphoid tissues, such as Peyer's patches in the small intestine, lymphoid follicles in the large intestine, and mesenteric lymph nodes. In the gut, leukocyte rolling and firm adhesion to the mucosal endothelium is initiated by signals from chemokines and is mediated via mucosal addressin cell adhesion molecule (MAdCAM)-1-associated sialyl Lewis X. Chemokine signaling induces the α4β7 integrin to undergo a change from low to high MAdCAM-1 binding affinity. The leukocyte then arrests and begins the process of extravasation through the vascular endothelium to underlying tissue. This extravasation process is believed to occur in both the normal immune cell recirculation state and in inflammatory conditions (von Andrian et al., supra). The numbers of α4β7+ cells in infiltrates and the expression of the ligand MAdCAM-1 are higher at sites of chronic inflammation such as in the intestinal tract of patients with UC or CD (Briskin et al., Am J Pathol 151:97-110 (1997); Souza et al., Gut 45:856-63 (1999)). α4β7 binds preferentially to high endothelial venules expressing MAdCAM-1 and vascular cell adhesion molecule (VCAM)-1, as well as to the extracellular matrix molecule fibronectin fragment CS-1 (Chan et al., J Biol Chem 267:8366-70 (1992); Ruegg et al., J Cell Biol 17:179-89 (1992); Berlin et al., Cell 74:185-95 (1993)). Together with constitutively expressed MAdCAM-1 in gut mucosal vessels, the α4β7 integrin plays a selective role in leukocyte gut tropism but does not seem to contribute to homing of leukocytes to the peripheral tissue or the CNS. Instead, peripheral lymphoid trafficking has been associated with α4β1 interaction with VCAM-1 (Yednock et al., Nature 356:63-6 (1992); Rice et al., Neurology 64:1336-42 (2005)).
Another member of the β7 integrin family, expressed exclusively on T lymphocytes and associated with mucosal tissues, is the αEβ7 integrin, otherwise known as CD103. The αEβ7 integrin binds selectively to E-cadherin on epithelial cells and has been proposed to play a role in the retention of T cells in the mucosal tissue in the intraepithelial lymphocyte compartment (Cepek et al., J Immunol 150:3459-70 (1993); Karecla et al. Eur J Immunol 25:852-6 (1995)). The αEβ7+ cells in the lamina propria have been reported to exhibit cytotoxicity against stressed or infected epithelial cells (Hadley et al., J Immunol 159:3748-56 (1997); Buri et al., J Pathol 206:178-85 (2005)). The expression of αEβ7 is increased in CD (Elewaut et al., Acta Gastroenterol Belg 61:288-94 (1998); Oshitani et al., Int J Mol Med 12:715-9 (2003)), and anti-αEβ7 antibody treatment has been reported to attenuate experimental colitis in mice, implicating a role for αEβ7+ lymphocytes in experimental models of IBD (Ludviksson et al., J Immunol 162:4975-82 (1999)).
Administration of monoclonal antibodies against alphaE beta7 reportedly prevents and ameliorates immunization induced colitis in IL-2−/− mice, suggesting that the onset and maintenance of inflammatory bowel disease depends on colonic localization of lamina propria CD4+ lymphocytes expressing alphaEbeta7 (Ludviksson et al., J Immunol. 1999, 162(8):4975-82). An anti-α4 antibody (natalizumab) reportedly has efficacy in treatment of patients with CD (Sandborn et al., N Engl J Med 2005; 353:1912-25) and an anti-α4β7 antibody (MLN-02, MLN0002, vedolizumab) reportedly is effective in patients with UC (Feagan et al., N Engl J Med 2005; 352:2499-507). A second anti-alpha4/beta7 antibody (AMG 181) is also in development and clinical trials have recently begun (clinicaltrials(dot)gov identifier, NCT01164904, September 2012). These studies and findings validate α4β7 as a therapeutic target and support the idea that the interaction between α4β7 and MAdCAM-1 mediates the pathogenesis of IBD. Thus, antagonists of beta7 integrin are of great potential as a therapeutic agent in treating IBD.
Humanized monoclonal antibodies targeted against the β7 integrin subunit have been described previously. See, e.g., Intn'l Patent Pub. No. WO2006/026759. One such antibody, rhuMAb Beta7 (etrolizumab) is derived from the rat anti-mouse/human monoclonal antibody FIB504 (Andrew et al. 1994). It was engineered to include human IgG1-heavy chain and κ1-light chain frameworks. Intn'l Patent Pub. No. WO2006/026759. Administration of etrolizumab to human patients according to certain dosing regimens has been described previously. See, e.g., Intn'l Patent Pub. No. WO/2012/135589.
RhuMAb Beta7 (etrolizumab) binds α4β7 (Holzmann et al., Cell 56:37-46 (1989); Hu et al., Proc Natl Acad Sci USA 89:8254-8 (1992)) and αEβ7 (Cepek et al., J Immunol 150:3459-70 (1993)), which regulate trafficking and retention of lymphocyte subsets, respectively, in the intestinal mucosa. Clinical studies have demonstrated the efficacy of an anti α4 antibody (natalizumab) for the treatment of CD (Sandborn et al., N Engl J Med 353:1912-25 (2005)), and encouraging results have been reported for anti α4β7 antibody (LDP02/MLN02/MLN0002/vedolizumab) in the treatment of UC (Feagan et al., N Engl J Med 352:2499-507 (2005), Feagan et al., N Engl J Med 369(8):699-710 (2013)) and also CD (Sandborn et al., N Engl J Med 369(8):711-721 (2013)) These findings help to validate α4β7 as a potential therapeutic target and support the hypothesis that the interaction between α4β7 and mucosal addressin cell adhesion molecule 1 (MAdCAM 1) contributes to the pathogenesis of inflammatory bowel disease (IBD).
Unlike natalizumab, which binds α4 and thus binds both α4β1 and α4β7, rhuMAb Beta7 binds specifically to the β7 subunit of α4β7 and αEβ7 and does not bind to α4 or β1 integrin individual subunits. This was demonstrated by the inability of the antibody to inhibit adhesion of α4β1+α4β7-Ramos cells to vascular cell adhesion molecule 1 (VCAM 1) at concentrations as high as 100 nM. Importantly, this characteristic of rhuMAb Beta7 indicates selectivity: T cell subsets expressing α4β1 but not β7 should not be directly affected by rhuMAb Beta7.
Support for the gut-specific effects of rhuMAb Beta7 on leukocyte homing comes from several in vivo nonclinical studies. In severe combined immunodeficient (SCID) mice reconstituted with CD45RBhighCD4+ T cells (an animal model of colitis), rhuMAb Beta7 blocked radiolabeled lymphocyte homing to the inflamed colon but did not block homing to the spleen, a peripheral lymphoid organ. See, e.g., Intn'l Patent Pub. No. WO2006/026759. In addition, the rat-mouse chimeric anti-murine β7 (anti β7, muFIB504) was unable to reduce the histologic degree of central nervous system (CNS) inflammation or improve disease survival in myelin basic protein T cell receptor (MBP-TCR) transgenic mice with experimental autoimmune encephalitis (EAE), an animal model of multiple sclerosis. Id. Furthermore, in two safety studies in cynomolgus monkeys, rhuMAb Beta7 induced a moderate increase in peripheral blood lymphocyte numbers that was largely due to a marked (approximately three- to sixfold) increase in CD45RA−β7high peripheral blood T cells, a subset that is phenotypically similar to gut-homing memory/effector T cells in humans. See, e.g., Intn'l Patent Pub. No. WO2009/140684; Stefanich et al., Br. J. Pharmacol. 162:1855-1870 (2011). In contrast, rhuMAb Beta7 had minimal to no effect on the number of CD45RA+β7 intermediate peripheral blood T cells, a subset that is phenotypically similar to naïve T cells in humans, and no effect on the number of CD45RA−β7low peripheral blood T cells, a subset that is phenotypically similar to peripheral homing memory/effector T cells in humans, confirming the specificity of rhuMAb Beta7 for the gut homing lymphocyte subpopulation. Intn'l Patent Pub. No. WO2009/140684; Stefanich et al., Br. J. Pharmacol. 162:1855-1870 (2011).
While clinical studies have demonstrated the efficacy of an anti-α4 antibody (natalizumab) for the treatment of CD (Sandborn et al., N Engl J Med 353:1912-25 (2005)), and encouraging results have been reported for anti-α4β7 antibody (LDP02/MLN02/MLN0002/vedolizumab) in the treatment of UC, there remains a need for further improvements in the treatment of these disorders. For example, natalizumab treatment has been associated with confirmed cases of progressive multifocal leukoencephalopathy (PML) in patients with Crohn's disease (and separately, multiple sclerosis) who received concomitant treatment with natalizumab and immunosupressives. PML is a potentially fatal neurological condition linked to reactivation of a polyomavirus (JC virus) and active viral replication in the brain. No known interventions can reliably prevent PML or adequately treat PML, if it occurs. One limitation of vedolizumab treatment is that it is administered intravenously which can be inconvenient for the patient and can also be associated with undesirable or adverse events, e.g., infusion site reactions. Accordingly, there is a need for improved therapeutic approaches to the treatment of gastrointestinal inflammatory disorders such as IBD, e.g., ulcerative colitis and Crohn's disease, as well as more desirable dosing regimens.
It is often unknown, prior to treatment, whether a patient will respond to a particular therapeutic agent or class of therapeutic agents. Accordingly, as IBD patients in general, and UC and CD patients in particular, seek treatment, there is considerable trial and error involved in the search for therapeutic agent(s) effective for a particular patient. Such trial and error often involves considerable risk and discomfort the patient in order to find the most effective therapy. Thus, there is a need for more effective means for determining which patients will respond to which treatment and for incorporating such determinations into more effective treatment regimens for IBD patients.
It would therefore be highly advantageous to have additional diagnostic methods, including predictive diagnostic methods, that can be used to objectively identify patients most likely to respond to treatment with various IBD therapeutic agents, including anti-beta7 integrin subunit antibodies. Thus, there is a continuing need to identify new biomarkers associated with ulcerative colitis, Crohn's disease as well as other inflammatory bowel disorders and that are predictive of response to anti-beta7 integrin subunit antibodies. In addition, statistically and biologically significant and reproducible information regarding such associations could be utilized as an integral component in efforts to identify specific subsets of UC or CD patients, such as TNF-IR patients, who would be expected to significantly benefit from treatment with anti-beta7 integrin subunit antibodies, for example where the therapeutic agent is or has been shown in clinical studies to be of therapeutic benefit in such specific UC or CD patient subpopulation.
The invention described herein meets certain of the above-described needs and provides other benefits.
All references cited herein, including patent applications and publications, are incorporated by reference in their entirety for any purpose.